Efficient Estimation of Active Element Patterns for 2-D Planar Array Antennas via Directional Decomposition

The active element pattern method is widely employed in beam pattern synthesis of array antenna to account for mutual coupling between antenna elements. Calculating the active element patterns for large number of array requires full-wave analyses of total array structure, which is time consuming. To obtain accurate active element patterns efficiently, this letter proposes a method to estimates active element patterns in largely arrayed antenna using directional decomposition approach. Reducing computational cost, proposed method constructs the transfer matrices to reflect both mutual coupling and truncation effects between each antenna element. Numerical validation with open-ended waveguides confirms that the proposed method can estimate active element patterns with high accuracy. The synthesized beam patterns show mean squared errors below 0.1dB in the main lobe region for various beam steering cases. The computational complexity for numerical analysis reduces from $\mathcal{O}(M_B^2(N_x^3 N_y^3))$ to $\mathcal{O}(M_B^2(N_x^3 + N_y^3))$, resulting in a reduction of computation time to under 0.095\% compared to the conventional active element pattern method.